How To Fit A Door Knob With Concealed Fixings

Door knobs with concealed fittings are an ideal choice if you are looking for a streamlined, neat design, without any visible screws or fixings. Watch our video and follow our step-by-step guide below for advice on how to fit this style of door knob.



Unboxing Your Door Knob

When your pair of door knobs arrive in their box, they will be fixed onto the mortice bar. The first thing you need to do is to remove the component parts. We are using the solid brass Mushroom door knob in a distressed silver finish as an example. This is a door knob with concealed fittings from our Old English Collection

The parts are as follows:

  • Pair of Solid Brass Mushroom Door Knobs with fixed roseplate.
  • 8mm mortice bar.
  • Inner roseplate plus plastic washer.
  • Fixing screws.

You can remove the door knobs from the mortice bar by using the Allen key to unscrew the grub screw. There is a hole located on the neck of the door knob and this houses the grub screw.

Mushroom Door PDF drawing with labels

The Mortice Bar

The mortice bar is 8mm wide metal bar that fits through your door. Each door knob is fixed to the mortice bar, on either side of the door. The mortice bar in our example has a helpful feature of a split at both ends, with a grooved indent. This helps to give a snug fit for the grub screw fixing as it is tightened down onto the mortice bar.

Detail of the grooved mortice bar for the Solid Brass Mushroom Door knob


The Inner Roseplate

In order to fit this type of door knob to the surface of the door, there is an inner/hidden roseplate with fixing holes. There is also a plastic washer to ensure the fitting is not loose. This inner roseplate needs to be unscrewed from the door knob prior to installation.

Inner roseplate on a door knob with concealed fittings


Step-by-step guide to fitting a door knob with concealed fittings

  • Insert the 8mm mortice bar spindle into your pre-drilled bore hole in your door, and through your tubular latch. For guidance on fitting tubular latches please see our previous video and guide HERE.
  • Place the inner roseplate over each end of the mortice bar so that it sits flush against the face of your door.
  • Fix the plastic washer in place.
  • If you have a door knob with bolt through fixings, make sure the correct pilot holes have been drilled that line up with the bolt through fixings on your architectural tubular latch.
  • For face fixing inner roseplates, make sure you have pre-drilled pilot holes and fit with the screws provided. Please note: the thickness of doors can vary, therefore make sure that you do not go into and damage the latch when you are tightening the screws.
  • Fix the door knob with its fixed outer rose plate onto the mortice bar and screw it onto the inner rose plate until it is tight against the surface of the door. Please make sure you line the grub screw hole up with the surface of the mortice bar with the grooved slit.
  • Tighten the grub screw using the Allen key.

 Your door knob is now fitted and ready for use!

Solid Brass Mushroom Door Knobs from the Old Emglish Collection

We hope you found this informative and helpful. If you have any questions don't hesitate to drop us a line. And why not take a look at Fitting A Reversible Tubular Latch: Tips & Advice or How To Hang A Door.



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1 comment

  • Jamie on Apr 12, 2023

    Hi I ordered a black mushroom door knob a few years ago and when fitting I lost one of the small screws that fit in to the handle. I have now found this but cannot locate my Allen key ! Can you advise if this a standard size or is a specific tool for this door knob?